This invention is concerned with the transportation of particulate solid material through a pipeline and in particular is concerned with the transportation of coal as a slurry in a stable foam carrier medium.
Large reserves of coal are known to exist in this country as well as others in regions which are remote from highly populated and industrialized centers where it is desirable to utilize the coal as fuels. Many of these remote areas where the coal reserves are located are also arid regions where water is scarce. Various methods including pipelining the coal in the form of slurries have been described for transporting coal to areas of intended use.
One of the major problems which has been recognized in the transporting of coal as slurries is that of maintaining the coal in suspension in the carrier liquid of the slurry.
In U.S. Pat. No. 2,672,370 there is described a method of transporting subdivided solids such as coal suspended in a liquid medium such as water through long distance pipelines and an improved pipeline system. In U.S. Pat. No. 3,617,095 there is described a process of transferring bulk solids through a pipeline by pumping the solids suspended in a pseudo-plastic fluid exhibiting nonNewtonian viscosity properties, as exemplified by thixotropic emulsions. In U.S. Pat. No. 3,637,263 coal is transported through a pipeline in a form of an aqueous slurry made up of a mixture of particulate coal and an inorganic finely divided water insoluble solid carrier having a specific gravity of at least 1.6. In U.S. Pat. No. 3,950,034 there is described a method of pipelining solids by suspending the solids in a liquid containing lamellar micelles and pumping the mixture at flow rates predetermined to produce retroviscous behavior in the liquid at noncryogenic temperatures.